The dramatic fires and evacuations — near Los Angeles and in the wine country of Northern California — came against a backdrop of power shut-offs that utility companies said were necessary to stop high winds from toppling trees or blowing debris into power lines and starting fires.
The state’s largest utility, Pacific Gas & Electric Co., warned more widespread blackouts this weekend were expected to shut power across much of the San Francisco Bay Area. It would be the third major outage this month.
Officials said they did not yet know how many homes had burned in the state, and that no immediate injuries were reported. It was not clear how any of the blazes began.
In Southern California, two fires rolled along the parched foothills north of Los Angeles, forcing at least 40,000 people to flee neighborhoods where thousands of homes have sprung up in recent decades.
At least six homes burned as the blazes swept through dry brush to the edge of communities in the Santa Clarita area. Winds gusting to about 40 mph pushed the flames, and enormous plumes of smoke were visible for many miles. People used hoses to try to protect their properties.
Los Angeles County Fire Chief Daryl Osby said on Thursday evening there was no containment of either blaze.
Hot and dry Santa Ana winds led Southern California Edison to cut power to more than 31,000 customers. It was considering additional power cuts to more than 386,000 customers.
In Northern California wine country, authorities ordered 2,000 people to evacuate as a wildfire burned 49 buildings and exploded to 25 square miles, whipped up by the strong winds that had prompted PG&E to impose blackouts.
A series of deadly blazes tore through the same area in Northern California wine country two years ago, killing 44 people.